Change LAN IP in LuCI (to an IP on a different subnet)

Issue: Can't change LAN IP in LuCI. After applying the changes, it fails and comes up with some dialogue box.

Root cause: This happens if the new IP is on a different subnet. It'is known and in fact deliberately designed to prevent the user from accidentally locking themselves out.

Solution: If you are confident that the new IP is correct, you have a few options:

• Choose Apply Unchecked in the dialogue box*/. This will apply the settings without checking if you can access the new IP or not, so double check the IP.
• If you prefer to not to bypass the check then you can do one of the following immediately (within 30 seconds) after changing the IP and applying the settings:
  1. Make your PC get a new IP (for example by disconnecting and reconnecting the cable or the WiFi, or via the terminal), then quickly edit the router IP in the browser Window to the new IP.
  2. Have prepared two static IPs for your PC LAN interface (one on the old IP range and the other in the new IP range), then after applying the settings in LuCI you quickly edit the router IP in the browser Window to the new IP.
• Connect with SSH and issue the commands:

uci set network.lan.ipaddr="192.168.2.1"
uci commit network
/etc/init.d/network restart